JP6939410B2 - Trance - Google Patents

Description

The present invention relates to a transformer.

Conventionally, a core, a primary winding made of a winding body wound around the core, and a secondary winding made of a metal plate material having a one-turn structure are provided, and the core is inserted through the metal plate material. A transformer characterized in that a through hole for holding the transformer is provided, a pair of terminal portions are formed across the through hole, and the winding body and the metal plate material are alternately arranged with respect to the core. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-013094

By the way, in a conventional transformer, the number of turns of all secondary windings is equal to each other, and all are one turn. When a plurality of primary windings and a plurality of secondary windings are arranged alternately, the leakage inductance between the primary winding and the secondary winding differs between the central portion and the end portion in the arrangement direction. ..

If there is such a distribution of leakage inductance (unbalance), the current flowing through the plurality of primary windings will be distributed. As a result, the copper loss becomes large, heat distribution occurs, and the temperature upper limit of the transformer may be partially exceeded.

Therefore, it is an object of the present invention to provide a transformer which suppresses the distribution of leakage inductance.

The transformer according to the embodiment of the present invention includes a core having a winding shaft, N (N is an integer of 3 or more) primary windings wound side by side on the winding shaft, and the N primary windings. Of the N + 1 secondary windings, including the N primary windings and N + 1 secondary windings that are alternately wound along the winding shaft so as to sandwich each of the wires. The number of first turns of the first secondary winding located at the end on the first end side of the winding shaft is the second secondary winding located second from the end on the first end side of the winding shaft. Of the N + 1 secondary windings, which is less than the second winding number of the wire, the third winding number of the third secondary winding located at the end on the second end side of the winding shaft is the winding number. The number of turns of the fourth secondary winding located second from the end on the second end side of the shaft is less than the number of fourth turns, and the first secondary winding and the second secondary winding are connected in series. At the same time, the third secondary winding and the fourth secondary winding are connected in series, and the first secondary winding, the second secondary winding, and the first secondary winding are connected in series. The secondary winding of No. 3 and the fourth secondary winding are connected in parallel, and the total number of the first winding and the second winding is the total number of the third and fourth windings. equal.

It is possible to provide a transformer in which the distribution of leakage inductance is suppressed.

It is a figure which shows the transformer 100 of an embodiment. It is a figure which shows the transformer 100 of an embodiment. It is a figure which shows the transformer 100 of an embodiment. It is a figure which shows the transformer 100 of an embodiment. It is a circuit diagram which shows the connection relationship of a primary winding 110 and a secondary winding 120A, 120B. It is a figure which shows the waveform of the current flowing through three primary windings 110. It is a figure which shows the transformer 100M of the modification of embodiment. It is a circuit diagram which shows the connection relationship between the primary winding 110 in a transformer 100M, and five secondary windings 120A, 120B, 120C.

Hereinafter, embodiments to which the transformer of the present invention is applied will be described.

<Embodiment>
1 to 4 are diagrams showing the transformer 100 of the embodiment. 1 is a perspective view, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIGS. 3 and 4 are side views. In the following, the description will be made using the XYZ coordinate system.

The transformer 100 includes a core 50, a primary winding 110, and secondary windings 120A, 120B. 3 and 4 show a substrate 10 on which the transformer 100 is installed. The substrate 10 is, for example, a FR-4 (Flame Retardant type 4) standard wiring board, and has a plurality of wiring layers (conductive layers).

The core 50 is made of a magnetic material such as ferrite, and has a main body 51 and a winding shaft 52. The core 50 holds the primary winding 110 and the secondary windings 120A and 120B.

The main body 51 has a rectangular parallelepiped outer shape, and has notches 51A and 51B on the Z-axis positive direction side and the Z-axis negative direction side. A part of the primary winding 110 and the secondary windings 120A and 120B are exposed (exposed) from the cutout portions 51A and 51B.

The winding shaft 52 is a columnar member extending in the Y-axis direction at the center of the XZ plane of the main body 51. The winding shaft 52 is integrated with the main body 51.

Since the core 50 as described above is composed of two members divided into two on the Y-axis positive direction side and the Y-axis negative direction side, the housing 51 and the winding shaft 52 are on the Y-axis positive direction side. And Y-axis are divided into two on the negative direction side. The two members are engaged along the seam 50A.

The primary winding 110 has ends 111 and 112, and has a structure in which a conducting wire is wound. The conductor is made of copper, for example. The primary winding 110 is wound around an annular bobbin 113. 1 to 4 show, as an example, a configuration in which the transformer 100 includes three primary windings 110. Electric power having a voltage higher than that of the secondary windings 120A and 120B and a lower current is supplied to the primary winding 110 from an external circuit.

The secondary windings 120A and 120B have terminals 121A, 121B, 122A, and 122B, respectively, and have a structure in which a metal plate is spirally wound. The metal plate is made of copper, for example. 1 to 4 show, as an example, a configuration in which the transformer 100 includes two secondary windings 120A and two 120B. That is, the transformer 100 includes a total of four secondary windings 120A and 120B.

The four secondary windings 120A and 120B are arranged in the order of the secondary windings 120A, 120B, 120B and 120A in the Y-axis direction, and are wound around the winding shaft 52. The secondary windings 120A, 120B, 120B, and 120A are wound around the winding shaft 52 in a state of being alternately arranged with the three primary windings 110.

That is, the secondary windings 120A and 120B are arranged on both sides of the primary winding 110 on the negative direction side of the Y axis, and the secondary windings 120B and 120B are arranged on both sides of the central primary winding 110 in the Y-axis direction. The secondary windings 120B and 120A are arranged on both sides of the primary winding 110 on the positive direction side of the Y-axis.

The number of turns of the secondary winding 120A is one, and the number of turns of the secondary winding 120B is two. In this way, four secondary windings 120A, 120B, 120B, 120A are arranged alternately with three primary windings 110, and two secondary windings 120B having a large number of turns are arranged on the center side to obtain the number of turns. By arranging a small number of two secondary windings 120A at both ends, the distribution of leakage inductance (unbalance) is suppressed. The detailed reason for this will be described later.

FIG. 5 is a circuit diagram showing a connection relationship between the primary winding 110 and the secondary windings 120A and 120B. In FIG. 5, the portion surrounded by the broken line is the transformer 100. Here, in FIG. 5, the secondary winding 120A located at the uppermost side is an example of the first secondary winding, and the secondary winding 120B located at the second highest position from the uppermost side is the second second. This is an example of the next winding. The lowermost secondary winding 120A is an example of the third secondary winding, and the second lowest secondary winding 120B is the fourth secondary winding. This is an example.

The three primary windings 110 are connected in parallel with the same polarity. Terminals 11A and 11B are connected to both ends of the three primary windings 110 connected in parallel. The terminals 11A and 11B are provided on the substrate 10 (see FIGS. 3 and 4).

For the four secondary windings 120A and 120B, the secondary windings 120A and 120B are connected in series one by one with the same polarity, and two sets of secondary windings 120A and 120B connected in series are connected in parallel. There is. By connecting in this way, the output voltages of the two sets of secondary windings 120A and 120B are matched. Terminals 12A and 12B are connected to both ends of the two sets of secondary windings 120A and 120B. The terminals 12A and 12B are provided on the substrate 10 (see FIGS. 3 and 4).

Further, such connection of the four secondary windings 120A and 120B is realized by connecting the terminals 121A, 121B, 122A and 122B to the conductive layer of the substrate 10.

FIG. 6 is a diagram showing waveforms of currents flowing through the three primary windings 110. Here, in FIG. 5, the current in the primary winding 110 shown in the upper _{I P1,} the current of the middle of the primary winding 110 _{I P2,} the current of the primary winding 110 shown in the lower and _{I P3.}

_{FIG. 6A shows the currents I P1} and I _P2 in a state where the distribution of leakage inductance (unbalance) between the three primary windings 110 and the four secondary windings 120A and 120B is suppressed. , _IP3 .

_{FIG. 6B shows the currents IP1} , _IP2 , and _IP3 of the three primary windings 110 of the transformer for comparison. The transformer for comparison has a configuration in which three primary windings 110 and two secondary windings having the same number of turns are alternately wound around a winding shaft 52. The number of turns of the secondary winding is 3 as an example.

In the transformer for comparison, the distribution (unbalance) of the leakage inductance is not suppressed, and the leakage inductance in the two primary windings 110 on both sides of the three primary windings 110 is 1 in the center. It is larger than the leakage inductance in each primary winding 110.

As shown in FIG. 6 (A), the transformer 100, since the distribution of the leakage inductance (unbalanced) are equalized is suppressed, the current value of the current _{I P1, I P2, I P3} is substantially equal.

On the other hand, as shown in FIG. 6B, since the distribution of leakage inductance (unbalance) is not suppressed in the transformer for comparison, the two outer primary windings having relatively large leakage inductance are used. The current values of the currents I _P1 and I _P3 flowing through 110 are smaller than the current values of the _{currents I P2} flowing through one central primary winding 110.

Thus, in the transformer for comparison, the current of the primary side _{I P1,} I _P2, I _P3 becomes unbalanced, leading to increase in the copper loss, causing distribution and partial temperature increase of the heat.

In the transformer 100 of the embodiment, in order to suppress such distribution (unbalance) of leakage inductance, three primary windings 110 and four secondary windings 120A, 120B, 120B, 120A are alternately arranged. Two secondary windings 120B having a large number of turns are arranged on the center side, and two secondary windings 120A having a small number of turns are arranged at both ends. The reason for adopting such an arrangement is as follows.

When three primary windings 110 and two secondary windings having the same number of turns are alternately wound around the winding shaft 52 like a transformer for comparison, the secondary side is viewed from the primary side of the transformer 100. At that time, there are secondary windings on both sides of the central primary winding 110 among the three primary windings 110. Therefore, the magnetic coupling between the central primary winding 110 and the secondary winding becomes dense, and the leakage inductance is relatively small.

On the other hand, since the primary winding 110 at both ends has a secondary winding on only one side, it is between the secondary winding as compared with the central primary winding 110 and the secondary winding. The magnetic coupling is sparse and the leakage inductance is relatively large.

Such a leakage inductance distribution (unbalance) causes a current imbalance as shown in FIG. 6 (B), causes an increase in copper loss on the primary side, and causes a heat distribution and a partial temperature rise. Let me.

Therefore, in order to suppress the distribution (unbalance) of leakage inductance and suppress the increase of copper loss, the distribution of heat, and the occurrence of partial temperature rise, as described above, the three primary windings 110 are alternated with each other. Four secondary windings 120A, 120B, 120B, 120A are arranged in the.

When three primary windings 110 are arranged, since the primary windings 110 exist on both sides of the central primary winding 110, the number of turns of the two secondary windings 120B sandwiching the central primary winding 110 is set on both ends. The number of turns is larger than the number of turns of the two secondary windings 120A.

As for the primary windings 110 on both sides, two secondary windings 120B are arranged on the center side, and one secondary winding 120A is arranged on the outer side. As a result, the magnetic coupling between each primary winding and the secondary winding is made substantially equal, and the leakage inductance is equalized.

In this way, the secondary windings 120A, 120B, 120B, 120A, which are one more than the number of primary windings 110 (3), are provided, and the distribution of the number of turns of the secondary windings 120A, 120B, 120B, 120A is 1. The distribution of leakage inductance (unbalance) is suppressed by increasing the number on the center side and decreasing on both outer sides, such as winding, volume 2, volume 2, volume 1, and volume 1.

Further, when the number of the secondary windings 120A and 120B is an even number, the arrangement of the secondary windings 120A and 120B becomes symmetrical when viewed from the central primary winding 110 among the odd number of primary windings 110. , The distribution of leakage inductance (unbalance) can be suppressed more effectively.

By connecting the secondary windings 120A and 120B one by one and connecting two sets of secondary windings 120A and 120B in parallel, the same output voltage as the secondary side of the transformer for comparison can be obtained. I am trying to get it.

As described above, according to the embodiment, it is possible to provide the transformer 100 in which the distribution (unbalance) of the leakage inductance is suppressed.

Further, since the terminals 121A, 122A, 121B, and 122B of the secondary windings 120A and 120B having a large amount of current are connected via the conductive layer of the substrate 10, heat can be dissipated through the conductive layer of the substrate 10. ..

In the above description, the mode in which the terminals 121A, 121B, 122A and 122B of the four secondary windings 120A and 120B are connected to the conductive layer of the substrate 10 has been described, but the terminals 121A, 121B, 122A and 122B are the substrates. It may be connected by a power cable instead of 10.

Further, in the above, the mode in which the transformer 100 includes three primary windings 110 and four secondary windings 120A and 120B has been described, but the number of primary windings 110 and secondary windings 120A and 120B is large. The number of secondary windings 120A and 120B is not limited to such a number, and the number of secondary windings 120A and 120B may be one more than that of the primary winding 110.

Further, it has been explained that when the number of secondary windings 120A and 120B is an even number, the distribution of leakage inductance (unbalance) can be suppressed more effectively as described above. The number of lines 120A and 120B may be an odd number.

FIG. 7 is a diagram showing a transformer 100M of a modified example of the embodiment. The transformer 100M includes four primary windings 110 and five secondary windings 120A, 120B, 120C, 120B, 120A. Other configurations are the same as those of the transformer 100 shown in FIGS. 1 to 5.

In the transformer 100M, four primary windings 110 and five secondary windings 120A, 120B, 120C, 120B, and 120A are alternately arranged and wound around a winding shaft 52. The secondary winding 120C arranged in the center of the secondary side has three turns.

FIG. 8 is a circuit diagram showing a connection relationship between the primary winding 110 and the five secondary windings 120A, 120B, and 120C in the transformer 100M. In FIG. 8, the portion surrounded by the broken line is the transformer 100M.

The primary side has a configuration in which the ends 111 and 112 of the four primary windings 110 are connected with the same polarity, and terminals 11AM and 11BM are connected to both ends of the four primary windings 110. The terminals 11AM and 11BM are provided on the substrate 10 (see FIGS. 3 and 4).

The secondary side has a configuration in which two sets of secondary windings 120A and 120B connected in series and a secondary winding 120C are connected in parallel, and two sets of secondary windings 120A and 120B and a secondary winding are connected. Terminals 12AM and 12BM are connected to both ends of the wire 120C. The terminals 12AM and 12BM are provided on the substrate 10 (see FIGS. 3 and 4).

Even in the transformer 100M having such a configuration, the distribution of leakage inductance (unbalance) can be suppressed as in the transformer 100 of the embodiment.

Although the transformer 100M including the four primary windings 110 and the five secondary windings 120A, 120B, and 120C has been described with reference to FIGS. 7 and 8, the primary winding 110 and the secondary windings have been described. The number of 120A, 120B, 120C is not limited to such a number, and the number of secondary windings 120A, 120B, 120C may be odd and one more than the even number of primary windings 110.

When the number is further increased, the number of primary windings 110 connected in parallel may be increased on the primary side, and the number of secondary windings 120C provided on the central side may be increased on the secondary side. That is, the secondary windings 120A and 120B connected in series on both ends may be arranged.

Although the transformer of the exemplary embodiment of the present invention has been described above, the present invention is not limited to the specifically disclosed embodiment and can be various without departing from the scope of claims. Can be transformed and changed.

100, 100M Transformer 50 Core 52 Winding Shaft 110 Primary Winding 120A, 120B, 120C Secondary Winding

Claims (3)

With a core with a winding shaft,
N (N is an integer of 3 or more) primary windings that are wound side by side on the winding shaft, and
Includes the N primary windings and N + 1 secondary windings that are alternately wound along the winding shaft so as to sandwich each of the N primary windings.
Of the N + 1 secondary windings, the number of first turns of the first secondary winding located at the end on the first end side of the winding shaft is from the end on the first end side of the winding shaft. Less than the number of second turns of the second secondary winding located second,
Of the N + 1 secondary windings, the third number of turns of the third secondary winding located at the end on the second end side of the winding shaft is from the end on the second end side of the winding shaft. Less than the number of 4th turns of the 4th secondary winding located in the 2nd position,
The first secondary winding and the second secondary winding are connected in series, and the third secondary winding and the fourth secondary winding are connected in series.
The first secondary winding and the second secondary winding, and the third secondary winding and the fourth secondary winding are connected in parallel.
The total number of turns of the first turn and the second turn is equal to the total number of the third turn and the fourth turn. The transformer according to claim 1, wherein the number of the first volume and the number of the third volume are equal, and the number of the second volume and the number of the fourth volume are equal. The (N + 1) of the secondary winding, 2M (M is Unlike N, 2 or more integer) Yes,
The transformer according to claim 1 or 2, wherein the N primary windings are 2M-1.

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